1. Field of the Invention
The present invention relates to an air conditioner in which a heat-source side unit having a compressor and a heat-source side heat exchanger is connected to plural use-side units each having a use-side heat exchanger by an inter-unit pipe so that the use-side units can perform cooling operation or heating operation at the same time and individually and independently perform any one of cooling operation and heating operation in a mixing mode.
2. Field of the Invention
There is known an air condition in which in which a heat-source side unit having a compressor and a heat-source side heat exchanger is connected to plural use-side units each having a use-side heat exchanger by an inter-unit pipe so that the use-side units can perform cooling operation or heating operation at the same time and individually and independently perform any one of cooling operation and heating operation in a mixing mode.
In this type of air conditioner, a water-refrigerant heat exchanger for heat-exchanging water and refrigerant is disposed as the heat-source side heat exchanger in the heat-source side unit, and water heated by a boiler (auxiliary heat source) is made to flow to the water side of the water-refrigerant heat exchanger under the heating operation of the use-side unit, thereby enhancing the evaporation capacity of the heat exchanger (for example, see JP-A-2-279962).
However, in the air conditioner disclosed in the above publication, the heat-source side unit is disposed outdoors, and the water-refrigerant heat exchanger is disposed in the heat-source side unit. Therefore, the water-refrigerant heat exchanger and a waster pipe are more cooled by outside air as the temperature of the outside air is lower. Under heating operation, that is, under low outside air temperature, hot water from boiler is supplied to the water-refrigerant heat exchanger, so that the hot water is cooled by the outside air and thus thermal loss occurs, so that the heat using efficiency of the boiler (auxiliary heat source) is lowered.